Today it is generally accepted that the final diagnosis of malignancy suspicious lesions has to be confirmed using biopsy techniques. The most commonly performed cell- and tissue-sampling techniques are fine needle aspiration (FNA) using mainly 23 G and 22 G needles (0.6-0.7 mm in diameter) and core needle biopsy (CNB) or vacuum assisted biopsy (VAB) needles using mainly 16-8 G needles (1.6-4.2 mm in diameter), with the latter two techniques dominating globally. Because of the significantly improved sensitivity and minimally invasiveness when combining needle biopsy techniques with imaging guidance the number of open surgical biopsies is steadily declining.
In contrast to FNA, CNB and VAB allow for large volume tissue sampling which permits differentiation between in situ and invasive lesions and histologic diagnosis of micro-calcifications.
There are significant advancements when it comes to visualization techniques continuously pushing the boundaries for what is possible when it comes to locating a suspicious lesion. In addition a number of developments like the use of advanced biomarkers for following and personalizing adjuvant treatment are defining new requirements concerning very precise and minimally invasive tissue sampling.
The distal end of biopsy needles used in most CNB and VAB devices is a sharp, solid tip, which is needed for penetration of tissue towards the location where a biopsy is to be taken. To penetrate suspicious lesions the needle has to be inserted manually or using the generally used spring-loaded mechanism to thrust the needle into the lesions with a predetermined length. Thereafter a tissue sampling procedure is initiated, usually incorporating the opening of a residual space which is filled with surrounding tissue and subsequently closed, whereby the tissue inside the residual space is severed from surrounding tissue.
The opening and possible closing of the residual space is usually accomplished by the relative movement of two separate elements of the needle biopsy assembly, e.g. an inner sampling needle relative to an outer cutting needle, an inner trocar relative to an outer sampling needle, or a distal cutting blade relative to a distal tip sampling needle.
Different types of biopsy devices are well known in the art. A few documents describing biopsy devices with hollow needles and elongated rods are US 2012/0029354, U.S. Pat. Nos. 5,188,118, 5,348,022, 5,121,751, 6,120,463, 8,282,573, 7,828,748, WO 2014/007380, DE 20211934U, U.S. Pat. Nos. 8,313,444, and 5,392,790. In EP 0966920 a fine needle and core biopsy device is disclosed, where the device comprises means for applying rotational and reciprocal movement to a cannula. A core biopsy arrangement has been described by the present applicant in EP2138104 and in EP 2323563, wherein a reciprocating longitudinal movement is applied to a biopsy needle. Further, the following documents describe biopsy arrangements comprising blades or severing arrangements: EP 1832234, WO 0010465, U.S. Pat. No. 5,615,690, RU 2212848, US 2009012423, WO 2008115526.
The sharp, solid tip of biopsy devices used today usually has a length of 5-15 mm. Given that lesions, e.g. in the breast, that can be detected with ultra sound guidance today have a median size of approximately 16 mm and can be as small as 4 mm, a sharp needle tip of such length causes problems. When sampling small tumors the needle tip complicates targeting the lesion. Furthermore the needle tip completely penetrates the lesion, causing unnecessary trauma and risking increased dissemination of tumor cells beyond the original extent of the tumor.
Placing the residual space of the needle inside the lesion is today achieved by either manually or automatically thrusting the needle into the desired location using a spring-loaded or electro mechanic mechanism. The thrust length of automated devices is usually 15-22 mm. CNB and VAB devices do not allow to place the needle precisely even with image guidance due to its significant penetration speed and thrust length. This disadvantage is usually compensated for by increasing the number of tissue sampling procedures or the sample needle diameter, thereby resulting in increased patient discomfort caused by augmented tissue destruction and bleeding. Additionally a fixed thrust length larger than 10 mm is unsuitable for smaller tumors, causing unnecessary patient trauma beyond the dimensions of the lesion.
Additionally, the manual insertion of large diameter needles through healthy tissue towards the targeted lesion can be cumbersome, especially if said tissue is dense. The physician has to apply manual force to navigate the needle towards the lesion while maintaining dexterity and control to not injure vessels and organs. The insertion process is a source of patient anxiety and should therefore be as short and efficient as possible.
To counteract today's shortcomings in biopsy devices a distal tip sampling device is needed that provides samples with a length equivalent to the insertion length into the tumor. Additionally the device should incorporate means to aid insertion through healthy tissue.
Several distinct challenges arise when employing distal-tip tissue arrangements, i.e. where the tissue sample is taken in a longitudinal direction at the distal tip of the biopsy needle.
The first challenge is related to filling the hollow needle with tissue. Preferably, the needle should be filled with tissue equivalent to the insertion length of the needle in the target lesion, i.e. the complete volume should be used for tissue collection to minimize unnecessary patient trauma. This proves problematic, especially taking into account the broad span of tissue properties found in lesions, e.g. in mammary tissue.
The second challenge is related to severing the tissue sample from the surrounding tissue once it is collected inside the hollow sampling needle. It is challenging to apply a reliable cutting mechanism at the distal tip of the needle that works for a broad span of tissue types without significantly increasing the overall cross section of the biopsy needle assembly.
Another challenge relates to the distal tip of the biopsy arrangement. It should be solid during insertion towards the lesion, thus preventing healthy tissue to enter the sampling needle. During insertion into the lesion it should be open and provide a sampling cavity. At the same time the construction must be able to withstand any aid in mechanical energy given to the biopsy arrangement.
Thus an objective of the present invention is to provide a distal-tip biopsy arrangement that reliably and effectively fills the needle with tissue during penetration of the tumor and that can aid insertion of the arrangement towards the lesion through healthy tissue.